1. Field of the Invention
The present invention is directed toward the lithiation of inorganic metal chalcogenides. More particularly, the present invention is directed toward a novel method of lithiating compounds of metal chalcogenides which exist or are formed in relatively well ordered crystal structures having a plurality of planes with relatively weak attractive forces between the planes, and the novel lithium intercalated products thereof.
As is known, because of the relatively weak forces between the planes of metal chalcogenides, it has been found possible in certain cases to introduce a wide variety of molecules between the planes to form products which are stable at ambient temperatures but which will lose the molecules between the planes under appropriate conditions. These intercalated products have shown many desirable properties including superconductivity and lubricating properties.
2. Description of the Prior Art
Various methods are known for the preparation of lithium intercalated metal chalcogenides, for example, see the following: Journal of Chemical Physics, Volume 58, page 697 et seq (1973); published German patent application 2,061,162; National Bureau of Standards Special Publication No. 364; pages 625 et seq (1972); Journal of Less Common Metals, Volume 20, page 121 et seq (1970); Science, Volume 175, page 884 et seq (1972); C. R. Acad. SC. Paris, 5., 276, Series C, page 1283 et seq (1973).
Basically, each of the foregoing references discloses preparative techniques that require extreme conditions or relatively sophisticated or complicated handling; and, each of the techniques often fail to yield suitable products. For example, insertion of lithium in the metal dichalcogenides by the foregoing techniques typically results in less than 0.7 moles of lithium being inserted in the metal dichalcogenide. Often multiphase products result which include unwanted molecules, such as ammonia or nitrogenous contaminants, being inserted within the planes of the transition metal chalcogenide.